Ralph Davis owned a frozen yogurt shop that was quite successful because it was the only shop within ...

Ralph Davis owned a frozen yogurt shop that was quite successful because it was the only shop within a three-mile radius of three high schools. The high school students and their families were his customer base. Ralph sold the yogurt shop to Denise Cole. Their agreement provided that Ralph would not start another yogurt shop within a five-mile radius of Denise's shop. The agreement between Ralph and Denise is:
 A) a void covenant not to compete.
 B) a violation of the Sherman Act because of its effect on competition.
 C) a valid covenant not to compete.
 D) a voidable covenant not to compete at Ralph's option.